An ankle injury can be devastating. The ankle is a complex joint including an intricate bone structure, muscles and tendons, ligaments and a neurological system. Rehabilitation of an injured ankle can be frustrating when attempting to isolate and selectively retrain the injured area.
The ankle moves in multiple planes. The ankle moves about an axis which passes transversely through the body of the talus bone by dorsi flexion and plantar flexion. Movement about the longitudinal axis of the subtalar joint accomplishes inversion and eversion of the foot. The ankle joint also moves by internal and external rotation.
Rehabilitative devices for the ankle and lower extremities have been described. These devices either strengthen damaged muscle or develop proprioception in the injured area. Open chain devices (U.S. Pat. No. 5,722,919) are non-weight bearing and are used to strengthen an injured area. Closed chain devices, or weight-bearing devices, most often are used to develop proprioception. Proprioception involves neuromuscular receptors in the skeletal muscles and on the surface of the tendons. These receptors provide constant feedback to the brain regarding movement, posture, changes in equilibrium, knowledge of position, weight, and resistance against its body parts. Using this feedback, the brain corrects or adapts to any changes in these circumtstances. Injury to the muscles or tendons of the ankle can damage the receptors affecting proprioception. The most popular device for developing proprioception and retraining the receptors in an injured area is a balance board. A platform rests upon a small centered fulcrum. As the platform rocks upon the fulcrum, the brain sends messages to various muscles of the lower extremities instructing them to correct the instability. In this manner, the brain re-educates or trains damaged receptors of the muscles or tendons. A variation of a balance board that has become the industry standard is described in U.S. Pat. No. 4,653,748. Additional, variations of balance boards are described in the following U.S. Pat. Nos. D405,135; 3,984,100; 4,635,932; 4,635,932; 5,603,334; 5,810,703; 5,891,002; and 5,897,474. Other rehabilitative and therapeutic devices for the ankle and lower extremities are described in U.S. Pat. Nos. 4,186,920; 4,739,986; 5,035,421; 5,112,045; and 5,368,536. Exercise magazines are replete with advertisements for ankle rehabilitative devices. These devices however are limited in that they only strengthen the damaged ankle or develop proprioception in the ankle. Further, these devices do not allow specific targeting of the muscles or tendons that require therapy.
From the foregoing, it is apparent that a need remains for a rehabilitative device for the ankle and lower extremities that can both strengthen an injured area and develop proprioception. This device would be most effective if the injured area could be specifically isolated and targeted for retraining and rehabilitation.
The device of the subject invention is a rehabilitative and exercise device for the ankle and lower extremities. The device comprises a platform to which the foot of a user is secured. The platform balances upon a self-gripping fulcrum. The user, by employing the muscles of the ankle and lower extremities, brings the platform from an initial position in which the platform rests upon the fulcrum and the floor to a balanced or neutral position in which the platform balances upon the fulcrum and is parallel to the floor.
The fulcrum can be moved freely to any position beneath the platform which allows specific muscles or muscle groups to be isolated and targeted for rehabilitation. Exercises on the device of the subject invention can be performed with an off-set center of gravity because the foot or feet are strapped to the board. This provides variable resistance levels for strengthening damaged or weak muscles.